NASA says planning is under way for a national memorial service for astronaut Neil Armstrong to be held in Washington sometime in the next two weeks. In the meantime, two NASA centers were holding public tributes Friday to the first moonwalker, who died Aug. 25 in Cincinnati at age 82, SPACE.com reported. A ceremony was conducted at the U.S. Space & Rocket Center, the visitor center for NASA\'s Marshall Space Flight Center in Huntsville, Ala. People gathered around the center\'s vertical Saturn V rocket display as red, white and blue balloons were sent aloft in astronaut\'s memory. A remembrance ceremony was held at the Kennedy Space Center in Florida, centered around its moon rocket exhibit at the Apollo/Saturn V Center. The Armstrong family has established \"Neil Armstrong New Frontiers Initiative,\" a memorial fund benefiting the Cincinnati Children\'s Hospital Medical Center. The family has asked that that in lieu of flowers, donations be made to the Initiative or to two scholarship funds set up in Armstrong\'s name by the Telluride Foundation and by the American Institute of Aeronautics and Astronautics. President Barack Obama has ordered flags be flown at half-staff on the day Armstrong is interred, although the family has not yet said publicly where or when that will occur.